Reduction of Cu2+ by isolated rat liver mitochondria.

The present work provided evidence that isolated rat liver mitochondria reduce the larger part of the added CU2+ and that the reduction is of important for copper accumulation in mitochondria. The process is rapid, energy-independent and affected by steric factors. Both mitochondrial thiols and cytochrome c could participate in the Cu2+-reduction. Blocking of these mitochondrial components decrease sharply but does not abolish the reduction ability of mitochondria. Copper ions undergoing reversible reduction and oxidation in the presence of cysteine and ferrocytochrome c lead to the formation of O2- and H2O2. Superoxide radicals arise only from reoxidation of Cu+.